1. Field of the Invention
This invention is in the field of energy management systems and more particularly a system for managing a large number of separate heating and cooling devices at separate locations.
2. Description of the Prior Art
Energy management systems are commonly used in those applications where a relatively large number of stations at separate locations which have individual energy requirements are managed by a central controller. In such systems each station reports to the controller the current conditions at the station and the controller determines the energy requirements for that station and transmits information to that station to control a local energy system at that station to bring the current condition to a desired condition.
For example, where the energy management system is for heating and cooling of each station the controller can receive the current temperature at each station and then transmit signals to control the station heating and cooling system to obtain a desired temperature at that station. The communication between the controller and each station is performed repetitively at frequent intervals to increase control quality. It is often necessary for one controller to communicate with a relatively large number of stations, in the order of hundreds, and therefore it is highly desired to minimize the length of the communication message to each station, the communication power requirements and the communication hardware.